ismn

Validates an ISMN (International Standard Music Number).

Options

Option	Type	Default	Description
message	string	locale default	Custom error message

Playground

Valid values

Value	Notes
"M-2306-7118-7"	Valid ISMN-10
"979-0-2600-0043-8"	Valid ISMN-13

Invalid values

Value	Reason
"M-230-22107-9"	Wrong check character
"INVALID"	Does not match ISMN format

Notes

• Empty string ("") always returns valid: true. Combine with notEmpty to require a value.
• ISMN identifies printed music publications. It starts with M (legacy) or 979-0 (ISMN-13).